Multi-stage differential amplifiers are known, for example, from the book "Operational amplifiers", Design and Applications, by G. GRAEME et al, published by McGRAW-HILL BOOK COMPANY, New-York, copyright 1971. Chapter 4 of this book deals with multi-stage differential amplifiers. A differential amplifier comprises, for example, two emitter-coupled transistors each having a collector load. The bases each receive an input signal and the outputs are available on the collectors. A multi-stage differential amplifier is simply formed by two or more of these stages in such a way that the output of a branch of a first stage is fed to the input of a branch of a second stage.
The present invention proposes a circuit arrangement for use in the field of wireless telephones, mobile receivers and all other receivers requiting balanced circuits with a low power consumption and low manufacturing costs for use in consmer products.
It is an object of the invention to provide a circuit arrangement having a differential gain as high as that of the prior-art circuit arrangements but having a lower power consumption.
It is another object of the invention to provide a circuit arrangement having a satisfactory signal-to-noise ratio.
It is a further object of the invention to provide a circuit arrangement having a common-mode rejection better than that of the prior art.